In vacuum processing of thin film materials, such as in the manufacture of semiconductor devices, multiple processing modules are typically interfaced to permit transfer of wafers between the interfaced processing modules. The transfer of wafers between interfaced processing modules is typically accomplished with the help of transport modules, which typically move the wafers through slots or ports provided in the adjacent walls of the interfaced processing modules. Transport modules may be used in conjunction with a variety of processing modules, which may include, among others, semiconductor etching systems, material deposition systems, and flat panel display etching systems. The particular arrangement of transport modules and processing modules is frequently referred to as “cluster tool architecture.”
In semiconductor process cluster tool architecture, the pressure within the transport module may be different than the pressure within an adjacent processing module. A gate drive valve may be used to isolate the various modules to: minimize leaks between a transport module that is at a different pressure than a processing module; minimize leaks between modules during pressure varying transitions; or to seal off a processing module from a transport module during processing.
In order to isolate a particular module, a gate valve may include a seal plate and a barrier door that seals off the particular module when engaged by the barrier door. The barrier door may include a vacuum seal that extends about the periphery of the door and a surface finished barrier seal face. The seal plate may include a barrier seal and a vacuum seal face. When the barrier door engages the seal plate in order to isolate the particular module, the vacuum seal of the barrier door may engage the mating vacuum seal face of the seal plate and the barrier seal of the seal plate may engage the mating barrier seal face of the barrier door. The seal plate sealing surfaces may be integrated into the chamber design, thus not requiring a separate seal plate, and the seal surfaces would be the chamber housing surfaces.
The barrier door may be fabricated from a metal, such as aluminum, by a process that involves anodizing the barrier door. Yet, such barrier doors can be prone to microcrack of the anodized surface thereby compromising the electrical and corrosive resistance of the anodized surface.
Accordingly, a need exists for additional methods of preserving the anodized metal surface of gate valve barrier doors.